Semiconductor laser module

Abstract

A semiconductor laser module includes a package; a plurality of semiconductor laser elements provided in the package; a member having a plurality of mounting surfaces on which the semiconductor laser elements are mounted, the mounting surfaces being separated from a bottom surface of the package by respective distances, the distances being gradually different from each other in a manner that the mounting surfaces as a whole form a step-like form; a plurality of lenses collimating respective laser beams emitted from the semiconductor laser elements; a plurality of reflection mirrors reflecting the respective laser beams; a condenser lens unit condensing the laser beams; an optical fiber where the optical beams condensed by the condenser lenses are optically coupled; and an optical filter disposed on optical lines of the respective laser beams reflected by the reflection mirrors and reflecting light having wavelengths different from the wavelengths of the laser beams.

What is claimed is: 
     
       1. A semiconductor laser module comprising:
 a package; 
 a plurality of semiconductor laser elements provided in the package; 
 a member having a plurality of mounting surfaces on which the semiconductor laser elements are mounted, the mounting surfaces being separated from a bottom surface of the package by respective distances, the distances being gradually different from each other in a manner that the mounting surfaces form a step-like form; 
 a plurality of lenses configured to collimate respective laser beams emitted from the semiconductor laser elements; 
 a plurality of reflection mirrors configured to reflect the respective laser beams; 
 a condenser lens unit configured to condense the laser beams; 
 an optical fiber where the optical beams condensed by the condenser lens unit are optically coupled; and 
 an optical filter disposed on optical lines of the respective laser beams reflected by the reflection mirrors and configured to reflect light having wavelengths different from the wavelengths of the laser beams. 
 
     
     
       2. The semiconductor laser module according to  claim 1 , wherein the condenser lens unit include two or more independent condenser lenses which condense the laser beams in a vertical direction and in a horizontal direction, respectively. 
     
     
       3. The semiconductor laser module according to  claim 2 , wherein the optical filter is disposed between two of the independent condenser lenses included in the condenser lens unit. 
     
     
       4. The semiconductor laser module according to  claim 1 , wherein the optical filter is tilted relative to optical axes of the laser beams reflected by the reflection mirrors. 
     
     
       5. The semiconductor laser module according to  claim 1 , wherein the optical filter is configured to reflect light having a wavelength greater than wavelength of the laser beams.